Acquired digital fibrokeratoma
ADF; acral fibrokeratoma; "supernumerary digit"-like fibrokeratoma
Acquired digital fibrokeratoma is a benign solitary fibrous papule of the digits — a firm, hyperkeratotic, pink or skin-coloured projection with a characteristic collarette of elevated skin at its base, almost always on a finger or toe of an adult. It usually arises following minor trauma and is often misinterpreted as a wart, supernumerary digit or cutaneous horn. Treatment is simple surgical excision (or shave + base electrodesiccation) with histological confirmation; recurrence after complete excision is rare.
Clinical features
- Solitary firm, dome-shaped or finger-like projection, 3–10 mm, with hyperkeratotic surface.
- Pink, skin-coloured or slightly translucent; collarette of slightly elevated skin around the base — the diagnostic clue.
- Distribution — fingers (commonest), toes; periungual region.
- Median age 30–60; both sexes; often a history of minor preceding trauma.
- Asymptomatic unless catching on clothing.
Histology
- Polypoid lesion with overlying acanthotic, hyperkeratotic epidermis.
- Core of dense vertically oriented dermal collagen bundles with scattered fibroblasts and small thin-walled vessels.
- Absence of nerve bundles distinguishes from supernumerary digit (which contains them).
Differential
- Verruca vulgaris (digital wart) — softer, punctate haemorrhages, often multiple.
- Supernumerary digit — usually present from birth, contains nerve bundles, ulnar aspect of fifth digit.
- Periungual fibroma (Koenen tumour) — multiple, autosomal-dominant tuberous sclerosis.
- Cutaneous horn — older patient, sun-damaged base; rule out underlying SCC/AK.
- Pyogenic granuloma — friable, bleeding, recent rapid growth.
Management
- Surgical excision under digital block — small ellipse including the base.
- Alternatively shave excision with light electrodesiccation of the base.
- Send tissue for histology.
- Recurrence after complete excision is uncommon.
- Multiple periungual lesions — refer for tuberous sclerosis assessment.
References
- Bart RS et al. Acquired digital fibrokeratoma. Arch Dermatol; 1968.
- Kint A, Baran R. Acquired (digital) fibrokeratoma. J Am Acad Dermatol; 1988.
Spot a correction?
If any clinical statement, citation or link on this page needs updating, please email admin@skinoncology.net with the page name, the proposed correction and the supporting source.